Eczema is the most common skin condition, especially in children. It affects one in five infants but only around one in fifty adults. It is now thought to be due to “leakiness” of the skin barrier, which causes it to dry out and become prone to irritation and inflammation by many environmental factors.

In addition, some people with eczema have a food allergy which can make eczema symptoms worse. In about half of patients with severe atopic dermatitis, the disease is due to inheritance of a faulty gene in their skin.  This gene encodes a protein called filaggrin. Unlike with urticaria (hives), the itch of eczema is not only caused by histamine, so anti-histamines may not control the symptoms. Eczema is often linked with asthma, allergic rhinitis (hay fever), and food allergy. This order of progression is called the atopic march.